In certain environments translucent windows or panels are preferred over transparent windows. For example, skylights in homes and in commercial and industrial buildings are often designed to keep out direct sunlight in order to reduce glare and to protect the interior of the building and its contents from the harsh effects of ultra violet light. Atriums, domes and clerestories are also often designed in this manner. In addition, structures which must admit light but which often must provide privacy as well, such as greenhouses and air-supported arenas, should preferably include translucent panels.
Translucent glass or plastic panels are readily available, but provide very little insulating value by themselves and would not be recommended for installations requiring protection against heat loss in the winter and heat gain in the summer. Translucent panels incorporating insulation material have been suggested, but they undesirably reduce the amount of light which the panels are capable of admitting. It would therefore appear that the requirements for insulating value and light transmission involve mutually restrictive qualities, and that improvement in one area would necessarily result in diminished performance in the other area.
It would obviously be highly beneficial to have an insulated translucent panel which provides good thermal insulation while at the same time being able to transmit adequate amounts of light, but prior to the present invention it did not appear possible to develop an economical panel with these characteristics.